hich metal is the best conductor of electricity? Choose from the choices below: Gold Aluminum Copper Mercury

| 5. Calculate Medium fine steel wool has a strand diameter of 0.002 inch. If 100 g of this steel wool were burned, what mass of iron oxide would you expect to be produced?

Willa weighs a clean, dry, empty crucible and finds it to have a mass of 95.83 g. After putting a spoonful of an unknown hydrate into it, she finds that the mass has increased slightly to 99.87 g. She heats the crucible and its contents, and finds that the mass has dropped to 97.22 g. Willa is told by her teacher that the molar mass of the anhydrous salt is 75.65 g.

Suppose you need 6.0 m of Grade 70 tow chain, which has a diameter of 3/8" and weighs 2.16 kg/m, to tow a car. How would you calculate the mass of this much chain? Set the math up. But don't do any of it. Just leave your answer as a math expression. Also, be sure your answer includes all the correct unit symbols. mass of chain- 0.0 X H 0²

1. XY,(aq) + T(s) – – > TX(s) + Y(s)

The mass of 2.21 x 1040 atoms of iron (molar mass = 55.845 g/mol) is 2.78 x 104 g. 2.05 x 102 g 30.97 g. O 6.22 x 103g O 112 × 10-2 g.

Platinum is a precious metal that is used as a catalyst for many important industrial reactions. Platinum can be purified by reacting platinum(IV) bromide solution with aluminium metal. To test this purification process, a student reacted 14.4 kg of aluminium metal with excess platinum(IV) bromide solution. After the reaction was complete, the student had extracted 75.4 kg of platinum metal. From this data, calculate the percent error of this experiment.Hint: Write a balanced chemical reaction equation and calculate the theoretical yield of platinum first.Do not show your work in the space provided.Record only your final answer with the correct number of significant digits and the proper units.

Crime scene investigators keep a wide variety of compounds on hand to help with identifying unknown substances they find in the course of their duties. One such investigator, while reorganizing their shelves, has mixed up several small vials and is unsure about the identity of a certain powder. Elemental analysis of the compound reveals that it is 67.31 % carbon, 6.978% hydrogen, 4.617% nitrogen, and 21.10% oxygen by mass.     Which of the compounds could the powder be? C17H19NO3C17H19NO3 = morphine, analgesic C17H21NO4C17H21NO4 = cocaine, illicit drug C7H5N3O6C7H5N3O6 = 2,4,6-trinitrotoluene (TNT), commonly used explosive C10H15NC10H15N = methamphetamine, stimulant C4H5N2OC4H5N2O = caffeine, stimulant C11H15NO2C11H15NO2 = 3,4-methylenedioxymethamphetamine (MDMA), illicit drug C21H23NO5C21H23NO5 = heroin, illicit drug C3H6NO3C3H6NO3 = hexamethylene triperoxide diamine (HMTD), commonly used explosive

What is the mass (in kg) of 6.89 × 10^25 molecules of carbon dioxide? Give the answer as a number. The units are understood to be kg.

A chemist prepares a solution of potassium bromide (KBr) by measuring out 31. mg of KBr into a 100. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to the correct number of significant digits. alo mol L